Technical Field
The present invention relates to an image reading apparatus and a semiconductor device.
Related Art
An image reading apparatus (scanner) using a contact image sensor, and a copying machine, a combined printer, or the like to which a printing function is added has been developed. As the contact image sensor used in the image reading apparatus, a configuration of using a photodiode which is provided on a semiconductor substrate is used.
For example, JP-A-5-207375 discloses a solid-state imaging element (imaging sensor) including a pixel (basic cell). The pixel includes a photodiode, a feedback capacitance element which accumulates photoelectric charges generated in the photodiode, an amplification circuit which uses an n-type MOS transistor, and a reset switching element for disconnecting an input terminal and an output terminal of the amplification circuit (source and drain of the n-type MOS transistor).
JP-A-5-207375 discloses that the capacitance value of the feedback capacitance element is decreased, and thus it is possible to improve sensitivity of a pixel. However, JP-A-5-207375 does not disclose details of a configuration of the feedback capacitance element or other elements for decreasing the capacitance value. That is, in the image reading apparatus (scanner) in the related art, a configuration of a pixel for improving the sensitivity in reading an image may be improved more.